Optical fibers have been widely used for the propagation of optical signals, especially to provide high speed communications links. Optical links using fiber optics have many advantages compared to electrical links: very large potential bandwidth, high noise immunity, reduced power dissipation and minimal crosstalk.
Recent advances in the fabrication of silicon based optical and optoelectronic integrated circuits have resulted in the making of optical waveguides with submicron cross sectional dimensions. Fiber optic cables have typically been edge connected to the sides of optical and optoelectronic integrated circuits, but this method is not readily useable for connecting to submicron waveguides, because of the large mismatch in cross sectional dimensions between a typical SMF fiber core and a submicron waveguide. There have also been recent advances in the design and production of grating couplers to connect to submicron waveguides, which means that optical fibers could be connected to the top of an optical integrated circuit, if a suitable connector were available.